Thyristors and Its Electrical parameter
A thyristor is any semiconductor switch with a bi-stable action depending on p-n-p-n regenerative feedback. Thyristors are normally two- or three-terminal devices for either unidirectional or bi-directional circuit configurations. Thyristors can have many forms, but they have certain commonalities. All thyristors are solid state switches that are normally open circuits (very high impedance), capable of withstanding rated blocking/off-state voltage until triggered to on state. When triggered to on state, thyristors become a low-impedance current path until principle current either stops or drops below a minimum holding level. After a thyristor is triggered to on-state condition, the trigger current can be removed without turning off the device. Thyristors are used to control the flow of electrical currents in applications including:
• Home appliances (lighting, heating, temperature control, alarm activation, fan speed)
• Electrical tools (for controlled actions such as motor speed, stapling event, battery charging)
• Outdoor equipment (water sprinklers, gas engine ignition, electronic displays, area lighting, sports equipment, physical fitness)
Electrical parameter of thyristor
VBO (Breakover Voltage) – Principal voltage at the breakover point
VDRM (Repetitive Peak Off-state Voltage) – Maximum allowable instantaneous value of repetitive off-state voltage that may be applied across a bidirectional thyristor (forward or reverse direction) or SCR (forward direction only)
IT (RMS) (On-state Current) – Anode cathode principal current that may be allowed under stated conditions, usually the full cycle RMS current
VRRM(Repetitive Peak Reverse Voltage) – Maximum allowable instantaneous value of a repetitive reverse voltage that may be applied across an SCR without causing reverse current avalanche
VGT (Gate Trigger Voltage) – Minimum gate voltage required to produce the gate trigger current
IGT (Gate Trigger Current) – Minimum gate current required to switch a thyristor from the off state to the on state
IH (Holding Current) – Minimum principal current required to maintain the thyristor in the on state